New development of self-interaction corrected DFT for extended systems applied to the calculation of native defects in 3C–SiC

Abstract

We recently developed a framework for implementing a scaled self-interaction corrected density functional theory (DFT-SIC) into pseudo-potential plane-wave DFT. The technique implements the original method of Perdew and Zunger by direct minimization of the DFT-SIC total energy functional. By using maximally localized Wannier functions, DFT-SIC calculation can be carried out efficiently even for extended systems. Using this new development, the formation energies of defects in 3C–SiC (silicon carbide) were calculated and compared to more standard DFT calculations. Differences of up to 1 eV were seen between DFT and DFT-SIC calculations of the formation energies. When compared to DFT, DFT-SIC produced less-stable vacancies and silicon interstitials, and more stable antisites and carbon interstitials. The most favourable interstitials were found to be C interstitials in a C+–C⟨100⟩ dumbbell configuration, with the formation energy of 5.91 eV with DFT and 5.65 eV with DFT-SIC. Si interstitials were not as stable as C interstitials. The most favourable Si interstitial was found to be Si tetrahedral surrounded by four C atoms, with a formation energy of 7.65 eV with DFT and 8.71 eV with DFT-SIC.